1. Technical Field of the Invention
The present invention relates to a mobile telecommunications system and, in particular, to providing different terminating call treatments to an incoming call based on the called mobile station's service area.
2. Description of Related Art
It is well known to provide different terminating call treatments for incoming calls within a telecommunications system. For example, an incoming call intended for a particular subscriber can be forwarded to the subscriber's designated forward-to-number, announcement machine, or answering machine. Furthermore, depending on the directory number associated with the caller, the incoming call may also be selectively screened and rejected. The intended subscriber may also receive a different ring signal depending on the category or the directory number of the incoming caller.
These different terminating call treatments are assigned and provided per each subscriber or subscriber group. For example, a telecommunications subscriber has to have a subscription agreement with his service provider for rerouting incoming calls to a specified forward-to-number. Such a subscription service includes Call Forwarding Don't Answer (CFDA), Call Forwarding Busy (CFB), Call Forwarding Variable (CFV), etc.
Unlike wireline telecommunications systems, mobile telecommunications systems have a limited number of channels available for providing mobile service to mobile subscribers within a particular service area. Some times, especially during peak service utilization, mobile subscribers are often unable to access mobile telecommunications service because all channels are being used. In a normal situation, this is not a problem for a mobile subscriber and the serving mobile telecommunications network. The mobile subscriber merely receives a congestion tone indicating that all access channels are currently being utilized and that another attempt should be made later.
In case of an emergency, however, such a lack of service due to congestion is undesirable, and it would be desirable to leave certain access channels available to enable mobile subscribers to make outgoing emergency or high priority calls.
An illustration of such an emergency situation is an earthquake or major civil unrest covering a particular mobile service area. In those situations, all of the mobile stations located within the particular mobile service area are affected and, as a result, the serving mobile telecommunications network provider would like to remain open the radio channels to enable the mobile subscribers to make outgoing emergency or high priority calls. Incoming calls terminating to the particular mobile service area during the emergency, however, could undesirably seize these certain channels. For example, when loved ones of mobile subscribers are informed of the emergency situation, a higher number of incoming calls tend to be generated to determine the safety of the subscribers. It would be advantageous if control could be exercised while terminating such incoming calls towards the service area covering the emergency situation.
The control over the termination of incoming calls may be of some benefit in other situations as well. Such a situation is where there is a major convention or meeting being held in a particular area. Preventing the termination of incoming calls to this particular area is necessary so that sensitive proceedings will not be disturbed. In other words, a "quiet" zone is desirable within this area. If a call attempts to terminate to this area, it would be desirable to reroute, for instance, to an operator or an announcement machine.